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need help on 2nd course!!!

07-23-2012, 02:55 PM

Hi folks,

I am on my 2nd course of a 42" pompeii build, I have been cutting my half bricks front to back, as many have to reduce mortar and help get a tight fit. I just mortared my first 3 bricks on the 2nd course, my first course was a 1/2 soldier course. My 2nd course angle is a little high, but matches the 21" mason string method. The issue I am having is on either side of the three bricks, the next brick I try and line up has a large gap where the bricks sit next to each other as they are placed flat on soldier course, pics show my problem.

Not sure what is going on, did I not cut these the right way? MY 42" is right on all the way around in regards to soldier course. Everything is real level.

I used the method of getting proper angle with string, then measureing where the string crosses front of brick to back of brick, that is what I cut and tapered off, I measured 1 brick, then cut the course (about 20 1/2 bricks). Will this angle change during each course.

I seen many that have the bricks tight top/bottom and side, which is what I ma trying to accomplish.

Should I tear the 3 bricks off and start from scratch?

It seems the problem is the soldier course is less wide and makes the transition of the circle better than a 4 1/2" 1/2 brick.

Comment

Looks like you have too much angle on each brick, which means the back is too wide. If anything, you want to have to small an angle so that the front of the brick will be tight and your mortar joint will be wider at the back.

Formula for the angle of each side is 90 degrees/number of bricks on a full course. And to answer your question, the angle changes based on the number of bricks you use on each course, but you can use that formula. Probably easier and more accurate than string

Comment

Nice start to your oven, Irelande5. Not to worry: gaps are normal. You control the size of the gaps by the degree of precision you employ in cutting your bricks. Simply 'shave off' the offending portion of brick that causes a gap, if you like.

Here is a list of the kinds of cuts you can make to create a tight fit and smaller mortar joint:

Angle cut - Looking at the brick from the top down, the brick is cut so that it is slightly narrower toward the side facing the inside of the dome than the outward-facing side. Kind of like a piece of pie with the pointy end chopped off. It reduces the size of the gap on the outside between adjoining bricks.

Taper - Looking at the brick from the side, again, it is narrower at the inside-facing end than the outside-facing end. These two cuts (top and bottom) create a wedge shape, and allows the large outside gap to be reduced. Tapered bricks come this way and are designed to build arches and vaults.

Bevel - This is the cut that leaves the 'shoulders' of the inside-facing surface of the brick narrower than the foot of the brick. It creates a trapezoid that eliminates the inverted 'V' shape between adjoining bricks as the circumference of the dome becomes smaller.

In the first pic below, the red lines are exaggerated, but illustrate the small amount of material that gets cut off in the process of beveling a brick. As each course progresses, the bevel angle increases, if only slightly. In the last pic, the bevel angle is acute.

Take a look at some of the other builds on the FB site and look at the degree of precision some of these guys have invested in. Les' build is the recognized standard for tightest joints and craftsmanship. Many builders prefer to get their ovens built asap while others feel their build is not a race and take the time required to ensure a level of quality they can live with.

Just know that the vast majority of ovens built throughout time (and by some of Italy's renowned builders of today) were constructed of bricks with rudimentary cuts and the gaps simply filled with mortar. An oven without gaps may look more pretty than one with gaps, but it won't cook any better.

Comment

Thanks Chip/deejayoh, should I take out the three bricks I have mortared in, or try and adjut the angles on the next bricks?

I agree with John, Leave the bricks in place and look at other builds, By the way look at John's build for an example of true craftsmanship, he is to modest to toot his own horn, so I guess I need to do it for him.

As you go up at some point you will need to go to smaller width bricks to keep the gaps at the top and bottom from getting to wide. you can use the cutoff pieces as shims on the back sides of your bricks.